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Blog posts of '2012' 'August'

Installing the Weber Carburetor

Installing a Weber 32/36 DGV, DGAV, DGEV

(For Weber Kits with 2 piece adapter)
These instructions are intended as a general guide for installation. Certain steps may vary slightly for different vehicle.
[Disassembly] [Bench Assembly] [Kit Installation] [Idle Setting]

Jetting Specifications
Jetting specifications of carburetors supplied in kits may vary slightly but will always be correct for the intended application.

TOOLS AND EQUIPMENT NEEDED PARTS SUPPLIED WITH INSTALLATION KIT
Combination, box or open-end Wrenches 1 ea. Weber 32/36 DGV, DGAV, DGEV
Socket set 1 ea. Carburetor Adapter (2 piece style)
Screwdrivers (regular and Phillips) 1 - hardware kit
Pliers 1 ea. Linkage kit
6mm Allen Wrench 1 ea. Chrome air filter
Gasket Scraper, Knife
Wiping rags, cleaning solvent
Gasket Sealer

TUNE-UP SPECIFICATIONS
All engine tune-up specifications for the WEBER carburetor remains the same as those specified by the factory for the original unit. Emissions tune-up should be carried out by a suitable qualified Dealer or Independent garage.
NOTE: Late model vehicles fitted with Emission Control Systems have many vacuum lines and electrical connections in their fuel systems. It is essential when dismantling the unit that disconnected lines must be identified with corresponding number tag or label system. Establish a function of any device disconnected or reconnected.

RECOMMENDED ADDITIONAL PARTS
1. Install a new fuel filter when installing this kit.
2. Many late model vehicles use high pressure fuel systems. The WEBER only requires 3.5lbs. of pressure. Check the pressure in your system and replace the pump if necessary.

Disassembly
1. Disconnect battery.
2. Remove the gas cap.
3. Drain some water from the cooling system. (enough so the water level in the engine is below the intake system) CAUTION: Hot water may be under pressure and dangerous
4. Remove factory air filter assembly and all attaching hardware and hoses. Use a tag and numbering system to identify hoses for re-installation.
5. Remove factory vacuum lines from carburetor, again use a tag and numbering system for reinstallation.
6. If emission control equipment is not used, disconnect and remove it completely. Leave the vacuum lines intact unless noted otherwise.
7. Remove fuel lines and disconnect throttle linkage from stock carburetor.
8. Loosen the carburetor mounting bolts and remove the stock carburetor.
9. Be sure to temporarily cap fuel line to prevent leakage and fire danger.
10. Clean carburetor-mounting surface on the intake manifold.
11. Plug all open vacuum and thermal switch fittings on the intake manifold.
Bench Assembly
1. Install the new redline lever on the carburetor. CAUTION: Do not over tighten throttle shaft nut.
Proper tightness can be achieved by installing nut just slightly more than finger-tight (finger tight then one more flat of the nut and bend lock tab. After tightening, open choke and check for full throttle operation from idle stop to wide-open throttle. If any sticking or binding occurs, loosen nut and re-tighten with reduced torque. If excessive torque has been applied, re-centralization of the throttle plate may be necessary. This may require loosening nut and raping on the end of the shaft with a small plastic mallet or a screwdriver handle (We are not driving nails here. Be firm but not abusive).
Kit Installation
1. Install the carburetor sandwich adapter as described below:
A: Coat the manifold base gasket with a suitable gasket sealer (gasgacinch or any grease equivalent substitute)
Install bottom adapter half to intake manifold. Use a 8mm counter sunk allen bolts to secure adapter to manifold and torque to 12ft/lbs.
B: Coat the intermediate gasket with gasket sealer. Use the four 6mm cap screws to attach the top plate with gasket to bottom plate and torque to 6 ft/lbs. DO NOT INSTALL MOUNTING STUDS BEFORE TOP PLATE HAS BEEN TORQUE DOWN.
C. Install the 8mm studs (if possible, use lock tight or stud mount). Do not over tighten the studs.
D: Install power brake or gross manifold vacuum device fitting in top adapter plate, if required for your installation. If the vacuum is  not used, plug hole or cap fitting (thread is usually 1/8th pipe). DO NOT OVER TIGHTEN FITTING PIPE THREADS THAT ARE TAPERED.
E: Set carburetor-mounting gasket in place over studs. Be sure to use gasket sealer on gasket.
2. With the linkage toward the rear of the vehicle on rear wheel drive vehicles or towards the right (passenger) fender on front wheel drive. Install the carburetor and provisionally tighten the nuts.
3. If linkage kit and cable bracket are supplied, install cable bracket on tow mounting studs on the side of the carburetor where the cable will pull towards. (See typical linkage layout in Bench Assembly section.
4. Place the cable through the trunnion supplied in the kit and check for full throttle operation and binding. NOTE: On some vehicles, the cable housing is threaded for fine adjustments to full throttle. Otherwise, use hole in lever best suited for your operation.
5. Install the fuel line on the WEBER (This is the fitting that is angled downward at a 45-degree). If the vehicle is equipped with a fuel return, be sure to cap off the return line.
6. Connect the vacuum advance line from the advance unit on the distributor to the carburetor (This is the larger uncapped brass tube in the base of the carburetor under the choke unit).
7. Connect the vacuum hose from power brake, if applicable to fitting installed in adapter.
8. Connect the electric choke and idle cutoff valve to a 12-volt ignition switch activated power source. NOTE: Do not connect to the (+) plus side of the ignition coil.
9. Reconnect the vehicle battery and replace the gas cap.
10. Start the engine. After warm-up, check for fuel leaks and air leaks around the carburetor mounting base and hose connections.
11. After the engine has warmed up to operating temperature, adjust the idle mixture and idle speed. Check for full choke off position and choke operation. Adjust choke element by loosening the 3 choke ring screws and turning the element in the proper direction, depending on your specific desire for early choke off or longer choke on timing.
12. With the choke off, follow the tune and adjustment carburetor for final setting on the adjusting procedure in the Additional Installation/Adjustment Instructions.
13. Final inspection is to check the space between the top of the carburetor and the bottom of the hood for adequate clearance.

Idle Setting
Warning: Failure to follow this procedure may cause rough idle, poor driveability and stalling and will void manufacturer's warranty.
The "Lean Best" idle setting procedure can be used to adjust your carburetor in the absence of an infrared exhaust gas analyzer. (Customers with an analyzer should proceed to set the idle mixture and speed to the vehicle's manufacturer's factory specifications.)
Note: Before adjusting carburetor, be sure engine is at operating temperature, (choke is off) air cleaner is removed and vacuum lines plugged off.

(1) The Weber DGV/DGAV idle speed screw should be adjusted to its "preliminary" set point before adjusting the idle mixture. To set the idle speed screw, follow these steps:
(2) Back "out" the idle speed screw until the tip of the screw no longer touches the throttle lever. Then slowly turn the screw in until it just comes in contact with the throttle lever.
(3) From the "contact" position, turn the idle speed screw "in" one (1) full turn.
(4) If a tachometer is available, install it prior to starting the engine. If a tachometer is not available set idle mixture 'by ear".
(5) Start engine. Be sure the choke is not engaged. Proceed to adjust the idle mixture.
(6) Turn the idle mixture screw "in" clockwise until the engine's RPM begins to fluctuate on the tachometer. (If adjusting by ear, until a noticeable drop in speed is heard).
(7) Back "out" (counterclockwise) the idle mixture screw slowly until the engine idle becomes steady. Try to obtain the leannest setting without affecting the idle spped. If necessary, repeat steps 6 and 7 until the best setting is achieved.
(8) Once the idle mixture is set, fine tune the engine's idle speed. If necessary, by adjusting the idle speed screw (Note: Turning "in" (clockwise), the idle speed screw will increase engine speed. Turning "out" (counterclockwise), the idle speed screw will decrease the engine speed).
(9) If idle speed is reset, go back and repeat steps 6 and 7.